Online fast measurement of section sizes of three-dimensional objects using binary image analysis

We propose a method for online measurement of section sizes of hot-rolled sections. We consider two main points. First, section sizes of the measured workpiece depend on its section outline; here the section outline is presented by perpendicularly intersecting the workpiece with an optical plane. Second, online measurement of section sizes is almost a real-time process; hereto shorten the measurement period, the recording process and the initial extraction process of one section outline are combined by recording it as three 2-D binary patterns. These patterns come from three areas of the section outline and are sufficient for calculating the section sizes. The experimental performance of this method was tested and verified in our laboratory and in a rolling mill in China. A set of the tests are presented. (C) 1998 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(98)00606-0].